Maritime regulations have long required the use of navigational "running" lights on boats and ships when the vessels are underway at night or in poor visibility conditions. Such lighting systems are well known and generally include lights of specified colors located on the bow and stern of the vessel. The bow lights are required to be green to starboard and red to port, whereas stern lights are clear. In this scheme, an observer can determine from the light pattern visible to him or her what direction a boat is moving. If an observer sees both red and green lights, it may be surmised that a boat is approaching head-on. On the other hand, if an observer sees only a red or green light, it can generally be assumed that a boat is either traveling on a non-intersection course parallel to that of the observer, or an intersecting course perpendicular to the observer's. For example, if an observer sees only a green light in its path, it may be assumed that a boat is passing from port to starboard in front of the observer's boat. Conversely, if only a red light is seen, this indicates a boat passing from starboard to port in front of the observer's boat. Spotting a white or clear light, without adjacent or also visible green or red lights indicates that the observer is directly astern of a boat.
On smaller boats, the red and green lights are typically contained in a common housing which incorporates a partitioned colored lens, or perhaps separate colored lenses. In contrast, larger boats or ships often have the running lights separated from each other, and frequently they are mounted along the ship sides, somewhat aft of the bow.
These navigational lighting systems or schemes have proven so reliable that their use on water craft is almost universal and similar systems have been designed for use with aircraft. However, while these lighting systems work well on a clear night, their effectiveness is significantly reduced in poor visibility conditions such as in clouds, fog, mist, rain, or snow. To compensate for such reductions in light visibility, air and water craft operators have developed auxiliary signalling systems to broadcast their position. For example, horns or bells have been used to alert others of a craft's position on the water. However, using horns or bells accurately is generally limited to larger ships or boats staffed with knowledgeable crews to broadcast and interpret the sounds. Smaller boats, such as pleasure boats, may include a small hand-held horn device, but its use is often haphazard and is frequently misunderstood by someone attempting to determine another boat's position from the timing and direction of the horn blasts. Although, more recently, sophisticated radar or electronic devices have been developed and refined to indicate the position of other craft in the vicinity of a boat or airplane, such equipment is expensive and its use is generally confined to only large, well equipped craft.
Also, in poor visibility conditions, the operator of an aircraft, watercraft or land-type vehicle may not see or otherwise be aware of objects in the path of the craft or vehicle, with the result that collisions with such objects may occur with resultant damage to the craft or vehicle and injury to the passengers thereof.
Accordingly, a need exists for an inexpensive means to increase the visibility of aircraft, water craft and the like in poor visibility conditions that is effective for small and large craft alike. Also, there is a need for a signaling system that does not require a boat operator to learn and interpret a set of sound signals to indicate a boat's path or direction. Moreover, there is a need for a signaling system for adverse light conditions that is simple and inexpensive to install on existing air, water and land craft, in addition to being provided as standard equipment on such craft. Additionally, there is a need for a simple and inexpensive system for detecting or marking an object in the path of an aircraft, watercraft or land craft in low visibility conditions to prevent a collision therewith. These needs have been satisfied by the invention described herein.